Ms. Smith, a 28-year-old associate editor for a publisher of construction magazines, on Wednesday put a contract on a quaint, three-bedroom house listed for $139,000 in Jacksonville’s Murray Hill neighborhood. She had missed out on the house once before, but the buyer who beat her to it eventually backed out of the contract, allowing her another shot.

“The market (prices) are going back up, and interest rates will go back up,” said Ms. Smith, who is represented by Amy Owens, a Realtor with Magnolia Properties. “I don’t want to wait too long and miss out on a good deal.”

Ms. Smith and other buyers across the U.S. are finding a different market this spring than in past years. Resurgent job growth, low interest rates and robust consumer confidence has expanded the ranks of would-be buyers. Meanwhile, the inventory of homes available for sale remains fairly scant.

In Jacksonville and many other cities this spring, those factors have created a market in which sales are brisk and many homes attract multiple offers. Last month, finalized sales of existing homes in Jacksonville were up 18% from a year earlier, and pending sales were up 30%.

Jackie and Michael Stephens had their three-bedroom home in Jacksonville listed for sale for 45 days, during which it had more than 20 showings, before it went under contract on March 28. The buyers, Jake Segers and Erica Robbins, offered the full price of $175,000 and required no conditions, beating out a competing bid.

“I’m floored. I’m absolutely floored,” Ms. Stephens said through tears of happiness after her Realtor, Magnolia’s Ms. Owens, informed them that the offer had been made. “And they’re not asking for closing costs. It’s all straight-and-narrow.”

The couple vacated the home in January to move to Orlando, where Ms. Stephens took a new job as an interior designer in the health-care industry at a 25% increase in pay and Mr. Stephens received an 11% raise by relocating to his company’s headquarters in Orlando. They’re renting in Orlando for a year so they can figure out in which neighborhood they want to buy a home.

Jacksonville’s new-home market is as busy as its resale market. Jacksonville builder Providence Homes, which specializes in homes priced from the upper $200,000s to the $500,000s, registered a 20% increase in sales in December through March from the same period a year earlier. “This is the best early spring that we’ve seen back to 2006,” Providence Chief Executive Bill Cellar said.

Similarly, ICI Homes, a closely held builder based in Daytona Beach, Fla., registered a 14% increase in its sales across northeast Florida in the first quarter in comparison to a year earlier, CEO Mori Hosseini said. ICI built 520 homes in total last year. “We see the velocity this year as by far better than last year,” he said.

Jenny Persson brought her two children and some friends on a road trip in late March from their current home in Falls Church, Va., to check out newly built homes in the Nocatee masterplanned community just south of Jacksonville. Between visiting with sales people in a Providence Homes model home there, Ms. Persson explained that her family favors northeast Florida’s weather, lifestyle and relatively lower costs than many other regions.

“As a family, we’ve been entertaining the thought of moving for four years,” Ms. Persson said. “We have the right financial climate, economic climate. The stars have aligned. I think a lot of people feel the same way.”

A home under construction by Providence Homes near Jacksonville, Fla., in late March.